1. Field of Invention
This invention pertains to hydraulic compressors used as a pressure wave generator, and more particularly to compressors for use as a driver for Stirling coolers or pulse-tube refrigerators with a free-floating diaphragm to reduce wear and tear thereof, thereby increasing the useful life of the compressor and reducing maintenance costs. The invention also relates to means for controlling the reciprocating movement of the diaphragm.
2. Description of the Prior Art
Compressors are used in a wide variety of applications for pumping fluids at different pressures from one environment to another. Frequently compressors include a diaphragm or another flexible member mounted in a chamber, and valve-controlled inlet and outlet ports connected to the chamber. (For the sake of brevity, the term diaphragm shall be used to describe any flexible member useful for fluid pumping). By connecting the single inlet/outlet port, or multiplicity thereof, to a fluid source and reciprocating the diaphragm, fluid can be pumped by the compressor efficiently. If necessary, multiple stage compressors may be employed. However, in all the prior art compressors, the extreme positions of the diaphragm were defined either by the walls of the chamber or by stops provided within the chamber. Therefore during each reciprocating motion, the diaphragm collided with, or at least made physical contact with the walls or the stops. These multiple contacts were a major source of wear and tear on both the chamber of the compressor, and the diaphragm itself. In fact frequently diaphragms wore away and broke down first because they were flexible and therefore less resistant to the collisions. Thus the prior art diaphragm compressor had to be overhauled relatively frequently. This feature was highly undesirable in certain important applications such as space stations where a compressor may be used in very critical functions such as pumping oxygen, and wherein maintenance is very difficult to perform at regular intervals.
Furthermore, as a result of the collisions between the diaphragm and the stationary members, particulate matter was produced which entered into and contaminated the fluid being compressed. This type of contamination is undesirable because the contaminant may react with the fluid, or render the fluid unclean.